detrans.ai 

Back to studies

Tinjauan sejawat menemukan klaim ‘otak berjenis kelamin’ bertumpu pada statistik yang cacat

Metode yang cacat dan kesimpulan yang berlebihan mengenai ‘otak berjenis kelamin’: tinjauan sejawat atas Kurth et al. (2022)

Komentar & analisisJenis kelamin, biologi & olahraga
Authors
Colin M. Wright, Adam M. Rochussen, Samuel G. Stagg
Journal
Theory and Society
Year
2026
Source
link.springer.com/article/10.1007/s11186-026-09747-2

Summary

A widely cited 2022 brain-scan study by Kurth and colleagues reported that the brains of 24 transgender women, before hormone treatment, fell between those of men and women, though closer to men. This 2026 critique argues the key difference from men only looked real because of lenient statistical choices: testing in one direction only, and not adjusting for making three comparisons. With standard adjustments, the difference from men could easily be chance, though the difference from women still holds. Small groups and one unusual result make it fragile. Sexual orientation, known to relate to brain structure, was never analysed though the data existed. The critique is plausible but uses only published figures, was accepted nine days after it was sent in, and its lead author is a Manhattan Institute fellow on the journal's advisory board.

Key findings

  • Studi 2022 membandingkan 24 laki-laki, 24 perempuan, dan 24 wanita transgender yang belum memakai hormon, menggunakan model komputer yang menilai otak pada satu skala laki-laki ke perempuan. Studi itu menyimpulkan otak wanita trans bergeser menjauh dari jenis kelamin lahir mereka menuju identitas gender mereka.
  • Studi itu hanya menguji perbedaan dalam satu arah. Menguji kedua arah, seperti lazimnya, membuat perbedaan utama wanita trans versus laki-laki menjadi lebih lemah. Menyesuaikan dengan fakta bahwa tiga perbandingan dibuat berarti hal itu mudah saja kebetulan.
  • Perbedaan yang lebih besar antara wanita trans dan perempuan akan tetap bertahan setelah penyesuaian ini. Jadi perselisihannya adalah tentang apakah otak wanita trans berbeda dari otak laki-laki, bukan apakah berbeda dari otak perempuan.
  • Dengan hanya 24 orang per kelompok, besarnya perbedaan apa pun tidak stabil. Satu hasil yang tidak biasa pada kelompok laki-laki tidak pernah diperiksa dengan menjalankan ulang analisis tanpanya.
  • Uji yang dipakai studi untuk membenarkan metode statistiknya lemah pada kelompok sekecil ini. Para pengkritik mengatakan metode yang membuat lebih sedikit asumsi setidaknya juga harus dilaporkan.
  • Dari 24 wanita trans, 6 tertarik pada laki-laki dan 18 pada perempuan. Orientasi seksual terkait dengan struktur otak, dan para penulis asli memiliki data ini tetapi tidak memperhitungkannya.
  • Setiap pengkritik berulang kali meminta data asli dan tidak mendapat jawaban, sehingga kritik ini bergantung pada angka yang diterbitkan. Mereka menyerukan agar data dirilis dan studi diulang oleh pihak lain.

Abstract

Kurth et al. (2022) concluded that the brain anatomy of transgender women is shifted away from their biological sex and toward their gender identity. We evaluate whether the study’s evidence supports this conclusion by focusing on its statistical methods and treatment of sexual orientation in its analyses. The principal finding relies on a very small sample, a weak justification for parametric analyses, one-tailed post hoc tests, no correction for multiple comparisons, and limited robustness testing. The study also did not properly account for sexual orientation as a potential neuroanatomical confound despite having the relevant participant data to do so. These methodological choices consistently bias the results toward smaller p-values and stronger apparent support for the authors’ stated hypothesis. The evidence presented therefore does not justify the study’s headline conclusion.

Conclusion

The analyses presented do not adequately support the paper's headline conclusion that transgender women's brains are shifted toward their gender identity. The evidence used to support that conclusion is weakened by a series of methodological limitations and poor choices, including a small sample size, parametric statistical methods, one-tailed post hoc hypothesis tests without correction for multiple comparisons, and the absence of several robustness analyses. The study also does not address sexual orientation as a potential confound, despite the authors possessing both the neuroanatomical and sexual orientation data needed to evaluate this possibility. These methodological choices and omissions consistently strengthen the perceived support for the authors' stated hypothesis while weakening confidence in the reported findings. Given the paper's unusually broad influence in neuroscience, medicine, journalism, law, and public policy, the methodological issues warrant careful consideration before the study can be cited as evidence supporting the hypothesis, and the authors welcome a response from the original authors and encourage public release of the anonymized participant-level data so that the findings can be independently replicated and evaluated.